Yes, running the bolt pulls a plunger back and cocks it, Nerf dart in the muzzle.
I will say that there are a lot more nuances to the setup of a Nerf gun than I ever imagined. Barely slept the night before his birthday, trying to make it work. It barely could make 10 feet. Then, about 3 hours before a dozen boys showed up for the party, I picked up one of the kid's Nerf guns and played with it for a few minutes. I noticed a feature in the "chamber" that had escaped me before. Back out to the shop to strip it down again and do some more machining on it. Wifey was going through the roof!
It would shot about 30 feet after the final modification.
So what's this special nerf chamber feature?